// TECHATRONIC.COM  
 // LIBRARY TM1637Display  
 // https://github.com/avishorp/TM1637  
 // LIBRARY RTClib   
 // https://github.com/adafruit/RTClib  
 #include <RTClib.h> 
 #include <TM1637TinyDisplay.h>  
 // Define the connections pins for TM1637 4 digit 7 segment display  
 #define CLK 3  
 #define DIO 4  
 // Define the connections pin for DS3231 RTC Module   
 // SCL - A5  
 // SDA - A4  
 // VCC - VCC  
 // GNG - GND  
 // Create rtc and display object  
 RTC_DS3231 rtc;  
 TM1637TinyDisplay display = TM1637TinyDisplay(CLK, DIO);  
 void setup() {  
  // Initialize the Serial Monitor at 9600 baud rate
  Serial.begin(9600);

  // Initialize the LED
  pinMode(LED_BUILTIN, OUTPUT);
 
  // Make the light flash to Indicate it has started
  digitalWrite(LED_BUILTIN, HIGH);
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
  digitalWrite(LED_BUILTIN, HIGH);
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);
  // Wait for console opening  
  delay(3000);  
  // Check if RTC is connected correctly  
  if (! rtc.begin()) {  
   Serial.println("Couldn't find RTC"); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(500);
   digitalWrite(LED_BUILTIN, LOW);
   delay(500); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(500);
   digitalWrite(LED_BUILTIN, LOW);
   delay(500); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(500);
   digitalWrite(LED_BUILTIN, LOW);
   delay(500); 
   while (1);  
  }  
  // Check if the RTC lost power and if so, set the time:  
  if (rtc.lostPower()) {  
   Serial.println("RTC lost power, lets set the time!");  
   digitalWrite(LED_BUILTIN, HIGH);
   delay(100);
   digitalWrite(LED_BUILTIN, LOW);
   delay(100); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(100);
   digitalWrite(LED_BUILTIN, LOW);
   delay(100); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(100);
   digitalWrite(LED_BUILTIN, LOW);
   delay(100); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(100);
   digitalWrite(LED_BUILTIN, LOW);
   delay(100); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(100);
   digitalWrite(LED_BUILTIN, LOW);
   delay(100); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(100);
   digitalWrite(LED_BUILTIN, LOW);
   delay(100); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(100);
   digitalWrite(LED_BUILTIN, LOW);
   delay(100); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(100);
   digitalWrite(LED_BUILTIN, LOW);
   delay(100); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(100);
   digitalWrite(LED_BUILTIN, LOW);
   delay(100); 
   digitalWrite(LED_BUILTIN, HIGH);
   delay(100);
   digitalWrite(LED_BUILTIN, LOW);
   delay(100); 
   // The following line sets the RTC to the date & time this sketch was compiled:  
   rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));  
   // This line sets the RTC with an explicit date & time, for example to set  
   // January 21, 2014 at 3am you would call:  
   //rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));  
  }  
  // Set the display brightness (0-7):  
  display.setBrightness(5);  
  // Clear the display:  
  display.clear();  
 }  
 void loop() {  
  // Get current date and time  
  DateTime now = rtc.now();  
  // Create time format to display:  
  int displaytime = (now.hour() * 100) + now.minute();  
  // Print displaytime to the Serial Monitor  
  Serial.println("Time Now:");
  Serial.println(displaytime);  
  // Display the current time in 24 hour format with leading zeros enabled and a center colon:  
  display.showNumberDec(displaytime, 0b11100000, true);  
  // Remove the following lines of code if  you want a static instead of a blinking center colon:  
  delay(1000);  
  display.showNumberDec(displaytime, true); // Prints displaytime without center colon.  
  delay(1000);  
 }